Traffic Signal Control Heads and Hardware

CITY OF HOUSTON STANDARD SPECIFICATION TRAFFIC SIGNAL LOOP DETECTOR

SECTION 16727

TRAFFIC SIGNAL LOOP DETECTOR

PART 1 GENERAL

1.1 SECTION INCLUDES

A. Loop Detectors This specification and detailed drawings describe the materials and installation procedures necessary to install loop detectors in roadways in the City of Houston. Basically, the inductive loop detector consists of a few turns of wire embedded in the roadway pavement which are connected to an electronic component mounted in a roadside cabinet. The detector is designed so that the passage of a vehicle over the loop in the pavement modifies the magnetic flux around the resonantly tuned loops of wire which is sensed by a transistorized unit that transmits the vehicle presence or passage to the traffic signal controller. Since traffic signal timing and sequencing are totally dependent on the quality and placement of the loops, craftsman type skills must be exercised on installation procedures. Loops may be adjusted by the Engineer, as necessary.

B. Card Rack Amplifiers

These specifications define the minimum acceptable design, operational and functional performance requirements for high performance, two-channel inductive loop vehicle detector units and data acquisition software that can provide binned traffic data and real-time traffic measurements on a vehicle-by-vehicle basis. The system shall provide current measurements and vehicle detection information on the last vehicle for use in local control, incident detection and advanced traffic management systems.

1.2 UNIT PRICES

A. Measurement This Item will be measured by the linear foot of sawcut containing loop wire and by each two (2) channel detector amplifier. Deviation of the Contractor from the layout on the drawings will require prior approval of the Engineer.

B. Payment

The work performed and materials furnished in accordance with this Item and measured as provided under “Measurement” will be paid for at the unit price bid for “Loop Detector Sawcut” for the various sizes and types of loop detectors specified 16727-1 09/02/04 CITY OF HOUSTON STANDARD SPECIFICATION TRAFFIC SIGNAL LOOP DETECTOR

on the drawings furnished and installed. This price shall be full compensation for furnishing, installing and testing the loop detectors; and for all labor, tools, equipment and incidentals necessary to complete the work.

Loop detector amplifiers as measured under “Measurement” will be paid for at the unit price bid for “Two Channel Detector Amplifiers” furnished and installed. This price shall be full compensation for furnishing, installing, and testing the loop detector amplifiers.

PART 2 PRODUCTS

2.01 LOOP DETECTOR MATERIALS

A. Contractor shall set up an adequate and safe traffic control based upon the Texas Department of Transportation Standard Drawing, “BARRICADES, CONSTRUCTION SIGNS AND TYPICAL CONSTRUCTION LAYOUTS FOR TRAFFIC SIGNAL INSTALLATIONS,” I-82-8011 BTS and the Texas Manual on Uniform Traffic Control Devices, latest revision.

B. Contractor shall draw all loop outlines on pavement for approval by the Engineer, prior to beginning sawcut.

C. As a minimum requirement, Contractor shall use a self-propelled power saw with diamond blade or abrasive saw blades for sawing the pavement to the length, depth and width as shown on the intersection layout plan and the typical detail drawings. The power saw must be equipped with a depth measurement device, water valve and guide.

D. Contractor shall locate water supply (hydrant or water truck) to cool the blade and to clean out slots. Hydrant can only be used if proper permission has been obtained and water meter is used.

E. Contractor shall have an air compressor for the cleaning and drying out the sawed slots on site.

F. Drill hole through pavement for conduit to pull box.

G. Flexible embedding sealer shall meet the following minimum specifications:

1. The flexible embedding sealer shall be designed to enable vehicular traffic to pass over the properly filled saw cut immediately after installation without tracking or stringing of the material. The flexible embedding sealer shall form a surface skin allowing exposure to vehicular traffic within 30 minutes at 75 16727-2 09/02/04 CITY OF HOUSTON STANDARD SPECIFICATION TRAFFIC SIGNAL LOOP DETECTOR

degrees F. And completely cure to a tough, rubber-like consistency in two to seven days after installation.

2. Properly installed and cured flexible embedding sealer shall exhibit resistance to effects of weather, vehicular abrasion, motor oils, gasoline, anti-freeze solution, brake fluid, deicing chemicals and salt normally encountered, in such a manner that the performance of the vehicle detector loop wire is not adversely affected.

3. Flexible embedding sealer shall be applicable to both Portland cement concrete andasphalt concrete pavements.

4. The flexible embedding sealer shall exhibit minimal shrinkage during or after its installation, and in no manner affect the performance characteristics of the material.

5. The flexible embedding sealer shall be designed to permit clean-up of material and application equipment with non-flammable solvents such as l.l.l. trichloroethane or Scotch-Grip Brand Solvent No. 4 (Prior to curing of flexible embedding sealer)). Should any flexible embedding sealer material be allowed to cure in the application nozzle, it shall be able to be pulled our as a solid plug.

6. The flexible embedding sealer shall have a minimum 12 month shelf life in undamaged original containers when stored in a cool, dry environment.

7. The flexible embedding sealer shall be designed for roadway installation when the surface temperature is between 40 degrees F and 140 degrees F.

8. The flexible embedding sealer shall have the following physical properties in its uncured and cured states.

Physical Properties of the uncured (wet) flexible embedding sealer: Property Requirement Test Procedures Weight 10.1 lbs/gal (+/- 0.5 Weight/Gallon lbs) Viscosity 10,000-85,000 CPS Viscosity Drying Time 24 hrs. (max) Tack-Free Time Skinning Time 6 hrs.

Physical Properties of the cured flexible embedding sealer: Property Requirement Test Procedure Hardness (Indentation) 65-85 Rex Hardness Tensile Strength 700 psi (min.) Tensile & Elongation Elongation 250% Tensile & Elongation

16727-3 09/02/04 CITY OF HOUSTON STANDARD SPECIFICATION TRAFFIC SIGNAL LOOP DETECTOR

H. Loop wire shall be IMSA Spec. No. 51-5-1984, #12 AWG, copper, stranded, single conductor pvc/nylon-with tube jacket. The maximum O.D. of the entire cable shall be 0.260 inches.

I. Contractor shall obtain megger and ohm meter for checking integrity of loop insulation and the continuity and resistance of the wired loop.

1. Wire must have a megger reading before installation (on reel);

2. Megger reading after installation (before being sealed);

3. Megger reading after being sealed and splices made;

4. It shall be the Contractor's responsibility to obtain these readings and have them available for the signal inspector upon request.

J. Splicing kit materials and equipment for splicing the two #12 wires to the shielded balanced pair cable in the pull box. Only soldered connections are acceptable. All splices must be watertight. The drain wire of the loop lead-in cable shall be grounded to earth ground only at the controller or detector cabinet. The resistance from the drain wire to the ground rod shall be less than one (1) ohm, at the cabinet.

K. The loop wire shall be held in place every two (2) feet with strips of rubber, neoprene flexible tubing or polyethylene foam sealant, one (1) inch in length. These strips shall be left in place and slot filled with loop sealant.

L. All wires shall be tagged to identify the loop number and lane. The tag identification shall correlate with the electrical schedule shown on the project plans. The tags shall be furnished and installed by the Contractor. Each tag shall be wrapped around the conductor twice. Wire marking tags shall be made of flame retardant reinforced epoxy tape 5.5 mils in thickness and ¼ inch minimum width. The tape shall be flexible and resistant to oil and water, and have a pressure sensitive acrylic adhesive backing. The adhesive shall be a high tack adhesive with good adhesion to clean neoprene, hypalon, nylon and PVC insulation materials. The film material shall conform to the flame retardant requirements of UL 510 and be rated at 150 degrees Centigrade. Appropriate numbers and letters shall be printed on wire tags for conductor identification.

2.2 CARD RACK DETECTOR AMPLIFIER

A. General Design Requirements

1. A communication link shall provide remote access to the detector for reading unit configuration settings, for fault identification and verification, for real-time system monitoring and data collection on up to two channels of detection. It shall include password security to the detector to change configuration settings. The communication link shall provide for party line communication on up to eight units using 4-bit hardwired addresses to the card edge connector and/or 127 software programmable addresses in EEPROM memory.

2. The interface and data acquisition software shall be organized by application and facilitate setup, real-time traffic monitoring and collection of binned count and occupancy data. A vehicle log shall provide a means for logging of vehicle speed, vehicle length, loop-to-loop travel time and detection duration. Optional modes of operation shall include a vehicle travel direction detection setup capability using overlapped 6-foot by 6-foot loops, a long-loop count mode to provide turning movement counts and a microloop mode selection when channels are connected to microloop sensors.

3. The successful bidder or contractor shall supply data acquisition and interface software and vehicle detectors that meet all the operational and functional performance requirements in accordance with the terms and conditions of this specification.

4. The bidder or contractor shall be responsible for any testing, rework and/or re- testing of equipment delivered under this contract that may be required to meet these specifications, at no expense to the City of Houston.

5. The bidder’s documentation shall indicate the manufacturer's name, address, model numbers, and include the shipping address for warranty repair work, as required in these specifications.

6. The City of Houston shall not be required to pay for software and/or hardware related modifications or changes and/or for associated labor that is required to correct errors.

7. The City of Houston shall be required to pay for any software and/or hardware- related modifications or changes and/or for associated labor that result from requested options, features or enhancements.

8. The City of Houston shall have the option to request and provide the communication protocols to a professional engineering consultant or OEM for 16727-5 09/02/04 CITY OF HOUSTON STANDARD SPECIFICATION TRAFFIC SIGNAL LOOP DETECTOR

integrating the data acquisition and interface software into its advanced traffic management system.

9. Serial numbers shall be clearly legible and permanently placed on each inductive loop detector unit.

10.Detectors shall be warranted against defects in workmanship or materials for five (5) years from date of purchase.

B. General Hardware - Standards and Performance Requirements

1. The inductive loop detector units shall be fully interchangeable, whether used for system counting, occupancy measurement, speed and length measurement, directional detection, binned data collection, remote data acquisition in advanced traffic management systems or for local intersection control (including long-loop counting).

2. Detector configuration data shall be entered using special interface and data acquisition software. A communication interface shall provide for remote connection and configuration of detectors, real-time activity monitoring and data acquisition via modem to remote devices.

3. Inductive loop detector units shall meet the latest edition of the National Electrical Manufacturers Association (NEMA) Standard TS2-1992 for Type 2 controller and cabinet assemblies plus the functional and performance requirements of this specification. The detectors shall be configured as plug-in devices which meet the requirements for NEMA TS2-1992 section 3.2, actuated Type 2 A2 operation and Type 1 A1 operation in 44-pin input files.

4. Detectors shall comply with NEMA TS2-1992 Section 6.5.2.2.1, Table 6.5-1 for four-channel rack mount type units, NEMA designation “D,” except that Delay and Extension Timing shall be provided on two channels in lieu of NEMA TS2- 1992 section 6.5.2.24 requirements.

5. Detectors shall also be suitable for use in California/New York TYPE 170/179 and ATC cabinets with 22-pin input files.

6. Detectors shall detect and hold the presence of all licensable motor vehicles (including small motorcycles). This shall be accomplished, without detecting traffic in the adjacent lane (beyond 36 inches from the loops except as noted below), on the following loop configurations with 100 up to 1000 feet of homerun cable.

One to six series connected, 6-foot by 6-foot square loops with three turns of #14 AWG wire.

One to six series connected, 6-foot by 6-foot square loops with four turns of #14 AWG wire.

A 6-foot wide by 30-foot long loop with two or three turns of #14 AWG wire (when set to detect small motorcycles, may detect adjacent lane traffic).

A 6-foot wide by 20-foot to 60-foot long quadrupole loop with a winding two-four-two turns of #14 AWG wire. When sensitivity is set to detect small motorcycles, adjacent lane traffic shall not be detected.

Single, double and triple microloop probe sets.

7. The detection performance described above shall be accomplished when using lead-in/homerun cable lengths of from 50 feet to over 1,000 feet of #14 AWG conductor homerun cable, i.e., International Municipal Signal Association, Specification #50-2.

8. A pushwheel switch shall be provided to allow selection of the threshold/sensitivity setting which will detect and hold presence of all licensable motor vehicles (including motorcycles), without detecting vehicles, moving or stopped, in the adjacent lane (36 inches from the loop connected to this channel, except as noted in 2.1.6.3).

9. Each channel shall automatically self tune with full sensitivity, to any loop and lead-in combination resulting in a total inductance of 20 to 2500 microhenries, with a Q factor of five or greater, within four seconds after application of power.

10. Detectors shall track changes in inductive loop or lead-in electrical characteristics that take place when environmental changes occur, which affect inductive loops installed in undamaged pavement, to insure that units operate properly without producing a false indication, a loss of detection or a change in sensitivity due to weather changes.

C. Special Features and Functional Performance Requirements

1. Detectors shall be microprocessor controlled and shall be configurable with manual switch settings and via software settings in EEPROM memory.

2. Detectors shall include eight sensitivity settings (thresholds), in 2:1 steps. Threshold settings shall directly relate to nanohenries of inductance change 16727-7 09/02/04 CITY OF HOUSTON STANDARD SPECIFICATION TRAFFIC SIGNAL LOOP DETECTOR

(Delta L). Detection output shall be based on a response to a change in the inductance which exceeds the Delta L threshold selected. For a given loop type, such as a 6-foot by 6-foot, three-turn square loop, it shall not be necessary to readjust the sensitivity setting to detect a specific vehicle type and/or to get consistent occupancy measurements using a range of lead-in or homerun cable lengths that vary from 100 feet up to 3500 feet.

3. Each detector shall have a single, switched oscillator system to sequentially excite and measure each channel to prevent crosstalk between channels within a unit.

4. Each detector shall have a three-position toggle switch to manually select one of three operating frequencies to reduce crosstalk between detector units. These three frequencies shall also be software selectable.

5. Each detector shall have two serial ports, a front panel RS232 port and transmit/receive pins on the card edge connector, to facilitate serial communication.

6. Each serial port shall have a multi-drop mode and be capable of party line communication with up to eight detectors on the party line.

7. The detector unit shall be designed to accommodate the addition of an optional plug-in communication module to allow expansion of the multi-drop capability to 32 devices on a common serial port bus and convert the rear port into an independent port. With the optional module installed, communication with a PC through the front port shall not interfere with system communication on the rear serial port.

8. Baud rates shall be selectable at 1200, 2400, 4800, 9600, or 19200 BPS using the interface software. With the communication module installed, the baud rates shall be independently settable for the front and rear serial ports.

9. The unit shall be designed to accommodate either an optional plug-in communication module or a plug-in memory module to expand the memory used for on-board count and occupancy binning.

10. The front panel serial port shall have EIA-232 electrical characteristics and shall terminate with a front panel 6-pin circular Mini-DIN connector.

11. A communication cable with a DB-9 female connector (for a computer serial port connection) and a 6-pin Mini-DIN male connector (for the front panel serial port connection) shall be provided with the interface and data acquisition software.

The communication cable shall enable direct communication with a remote reporting device or a PC running WindowsÔ 95 or WindowsÔ NT 4.0.

12. Units shall have software settable addresses from 128 to 254. Address 255 shall be assigned as a "wildcard" to be used only when connected to the front panel port to establish connection and read the correct address from the device.

13. Units shall have 4-bit back panel hardwired addressing capability to allow selection of one of 16 hard-wired addresses. Back panel addressing shall be enabled via the interface software.

14. An external 24VDC Green control input shall be provided to control the output timing. If True (ground level = 0 to +8VDC), the Green input shall disable Delay and enable Extension Timing; and if False (+16 to +30VDC or Open), the Green input shall disable Extension and enable Delay Timing. Software shall provide for an option to disable Green Gating so that Delay or Extension Timing is provided unconditionally.

15. Detector units shall have a Presence or Pulse mode output option. Selection shall be via front panel switches or software settable options.

16. Each channel shall have a pushwheel sensitivity switch to enable manual selection of the output mode and sensitivity (threshold) settings as follows:

The pushwheel switch shall have an OFF mode position indicated by an “X” marking. This position shall disable each channel's output and front panel Detect and Fault indicators.

The pushwheel shall have seven Presence mode sensitivity settings.

The pushwheel shall have eight Pulse mode sensitivity settings. Pulse mode settings shall use a square-wave marking over the channel sensitivity numeral to differentiate from Presence mode settings.

17. Each increase in Presence or Pulse mode settings shall double the sensitivity (reduce the threshold) from the previous setting.

The highest sensitivity (smallest change) setting shall have a Delta L threshold value of eight nanohenries.

The lowest sensitivity setting shall have a Delta L threshold of 1024 nanohenries.

18. Presence output shall hold vehicle detection for at least four minutes minimum for small licensed motor vehicles (100cc. motorcycles) and for at least 60 minutes for automobiles before tuning-out vehicles (dropping recognition of vehicle presence) over a 6-foot by 6-foot square loop with three or four turns of wire.

The presence output shall not tune out when vehicle motion exists (defined as vehicle entry and departures continue every few minutes and vehicles remain present in the sensing zone) for at least 60 minutes.

19. In Fast Recovery mode the channel shall recover to full sensitivity within 750 milliseconds after all vehicles leave the inductive loop sensing zone.

20. Pulse mode shall provide a single, 118±5 millisecond, output pulse in response to an 18-foot long vehicle traveling over a 6-foot by 6-foot loop at eight miles per hour, and for successive vehicles traveling over the same loop at speeds ranging from ten to 100 miles per hour, with a one second headway. Pulse width shall be programmable from interface software.

If a vehicle remains over the loop, further detection shall be inhibited for a 1.9-second re-phase delay. Then full sensitivity shall return immediately regardless of continued presence of the vehicle. Pulse re-phase shall be programmable from interface software.

21. Detector units shall have optically-isolated FET outputs to provide fail-safe solid state operation (loss of power to the detector will provide a constant call to the controller--if it has power).

22. Loop detector channels shall continue to function with a single point to ground on the loop/lead-in system.

23. Each channel shall have loop measurement capability to continuously verify loop system integrity. The loop detector shall be capable of detecting and displaying current and historical faults (a short to ground, an open circuit or an inductance change ³ 25%) in the inductive loop or lead-in system.

24. Each channel shall have two LED indicator lights on the front panel; a green "Detect" LED and a red "Fault" LED.

25. The green "Detect" indicator shall indicate detection output status and output timing in process.

26. It shall indicate an Extend flash while the call output is actuated following a directional detection. 16727-10 09/02/04 CITY OF HOUSTON STANDARD SPECIFICATION TRAFFIC SIGNAL LOOP DETECTOR

27. The green "Detect" indicator shall flash during Delay and Extension Timing to provide a visual indication of timed output.

Delay and Extension flash rates shall differ by at least four times the other's rate. Delay shall be four flashes per second and Extension shall be 16 flashes per second.

28. The green "Detect" indicator shall be ON continuously during a fault condition unless fail-safe for a particular condition is disabled using the interface software.

During a fault condition on a channel, the channel shall display a continuous call indication on its green “Detect” LED and generate a continuous, fail-safe, output on the primary output, regardless of the Pulse or Presence operating mode selected.

29. A status output shall provide a serial coded message to external devices (controllers) that are capable of using the serial information in accordance with NEMA conventions described in TS2-1992.

30. A red "Fault" LED shall indicate current or historical channel fault condition (status) and type. The Fault indicator shall flash a coded message during an open loop condition, a shorted loop system condition and a ³ 25% change of inductance condition. The associated channel’s red “Fault” LED shall provide visual indication of fault type and status as follows:

OFF state indicates no faults (current or historical).

ON for one second and one .25 second short pulse indicates a current open loop fault.

A one second ON and two .25 second short pulses indicates a current shorted loop fault.

ON for one second and three short pulses indicates a current greater than 25% change in inductance fault.

A long pulse (six second) followed by a short pulse (.25 second) indicates a historical open.

A long pulse followed by two short pulses indicates a historical shorted loop.

A long pulse followed by three short pulses indicates a historical greater than 25% change in system inductance fault. 16727-11 09/02/04 CITY OF HOUSTON STANDARD SPECIFICATION TRAFFIC SIGNAL LOOP DETECTOR

31. A fault indication shall be enabled for as long as the fault remains, except by turning the channel OFF in software or by selecting the “X” setting on the sensitivity switch.

32. If the fault heals or is corrected, the affected channel shall immediately retune and be capable of normal detection. The visual fault indication shall remain active until reset by a momentary change in the mode or sensitivity setting, a momentary interruption of power or by pressing a reset switch.

33. Call output for each detector channel shall provide detect durations in response to an automobile over a three or four turn 6-foot by 6-foot square inductive loop to enable accurate speed, length and occupancy measurements by external devices.

The detector with a 100 microhenry loop/lead-in attached to each channel shall, for any negative inductive change which exceeds its sensitivity threshold, generate a ground true logic level output response within 13 milliseconds for a sensitivity setting of 128 nanohenries.

The detector with a 100 microhenry loop/lead-in attached to each channel shall, for any negative inductive change which exceeds its sensitivity threshold, generate a ground true logic level output response within 20 milliseconds for a sensitivity setting of 64 nanohenries.

34. The output shall become open within the same time limits when such an inductive change is removed.

35. Loop detectors shall have a multi-position switch to Reset all channels and to provide Normal and Fast Recovery modes of operation.

The Fast Recovery setting shall cause the detector to adapt instantly to large changes of apparent inductance in the non-call direction.

The Normal Recovery mode shall cause the detector to adapt, at a default rate of 0.5 thresholds per second, to apparent changes of inductance in both directions.

36. Loop detectors shall have a Remote Reset input pin on the card edge connector. The unit shall reset and establish a new reference for each loop that is turned ON, when voltage on Pin C is less than eight volts DC for a period of greater than 17 milliseconds.

37. Delay Timing shall be adjustable from zero to 31 seconds, minimum, in increments of 1.0 seconds in lieu of NEMA TS2-1992 section 6.5.2.24.1 increments. When Green Gating is enabled (using the interface software) delay timing shall only occur if the green input is false.

38. Extension Timing shall be adjustable from zero to 7.75 seconds, minimum, in increments of 0.25 seconds in lieu of NEMA TS2-1992 section 6.5.2.24.2 increments. When Green Gating is enabled (using the interface software) extension timing shall only occur if the green input is true.

39. Setting the Delay or Extend DIP switches on the printed circuit board to OFF or selecting 0.0-seconds shall disable timing for that channel unless the override switch is off and Configuration Source is selected to be EEPROM using the interface software.

40. Each channel shall be capable of being assigned a Long-loop Count mode using the software.

Each channel enabled for Long-loop Count mode shall count each individual vehicle moving onto or over a single inductive loop which has a length greater than 20 feet, regardless of previous vehicles being stationary on, moving over or leaving the detection zone.

Each channel shall be configurable for Long-loop Count mode via the serial communication ports.

The Long-loop Count shall be readable via the serial ports.

The call output in the Long-loop Count mode shall be a Presence output.

41. Two channels (channels 1 and 2) shall be capable of being assigned to Directional Detection mode using the software.

The two channels shall be capable of detecting the direction of travel of a vehicle over two 6-foot by 6-foot overlapping loops.

The leading edge to leading edge spacing of the overlapping loops shall be three feet.

The directional count shall be stored in the detector and shall be accessible via the serial ports.

The directional count shall be stored in the second channel that detects the vehicle in the direction of the vehicle’s travel. 16727-13 09/02/04 CITY OF HOUSTON STANDARD SPECIFICATION TRAFFIC SIGNAL LOOP DETECTOR

A call output shall be generated by the second channel that detects the vehicle in the direction of the vehicle’s travel.

42. The vehicle detector unit shall be capable of collecting and storing counts and occupancy in time bins for each channel.

The time bin interval of the vehicle detector shall be configurable from the serial port using the software.

The memory of the vehicle detector shall be capable of storing count and occupancy data in 15 minute time bins for all four channels for 36 hours.

The vehicle detector shall be designed to accommodate a plug-in memory module to expand the on-board memory used for storing the count and occupancy time bins.

With optional memory module, the vehicle detector shall be capable of storing count and occupancy data in 15-minute time bins for all four channels for 335 hours.

The count and occupancy stored in the time bins shall be retrievable remotely using the serial ports.

D. Connector Pinout Configuration

The following input-output connector pin terminations shall be provided on input file connectors as well as detector edge connector in accordance to NEMA TS2-1992 section 6.5.2.27.2, Table 6.5.8 requirements.

The detector’s edge connector pinout is specified in the table below and is shown looking into the front of a detector card rack or input files. Pin-1 is at the top of the component side of the detector and Pin-A is at the top of the non-component side of the detector.

FUNCTION / SIGNAL PIN PIN FUNCTION / SIGNAL CH 1 GREEN DC+ 1 A DC GND CH 2 GREEN DC+ 2 B POWER (+10.8 to 37VDC) DET ADDRESS 3 3 C REMOTE EXTERNAL RESET LOOP IN CH 1 4 D LOOP IN CH 1 LOOP IN CH 1 5 E LOOP IN CH 1 DET ADDRESS 0 6 F CH 1 OUT + STATUS OUTPUT CH 1 7 H CH 1 OUT - LOOP IN CH 2 8 J LOOP IN CH 2 LOOP IN CH 2 9 K LOOP IN CH 2 16727-14 09/02/04 CITY OF HOUSTON STANDARD SPECIFICATION TRAFFIC SIGNAL LOOP DETECTOR

DET ADDRESS 3 10 L CHASSIS GROUND NO CONNECTION 11 M NO CONNECTION NO CONNECTION 12 N NO CONNECTION NO CONNECTION 13 P NO CONNECTION NO CONNECTION 14 R NO CONNECTION

DET ADDRESS 2 15 S NO CONNECTION NO CONNECTION 16 T NO CONNECTION NO CONNECTION 17 U NO CONNECTION NO CONNECTION 18 V NO CONNECTION DATA TRANSMIT 19 W CH 2 OUT + STATUS OUTPUT CH 2 20 X CH 2 OUT - DATA RECEIVE 21 Y NO CONNECTION NO CONNECTION 22 Z NO CONNECTION

E. Interface Software Requirements

(for setting up communication and data collection, configuring binning, logging, travel direction detection, viewing diagnostics, fault monitoring and parameter setting features)

1. The detector unit shall be capable of remote configuration, system diagnostic measurements and real-time data collection. A communication link shall provide remote access to the detector, for reading its configuration, for fault identification and verification, for real-time monitoring and data collection on two channels. The link shall provide optional password protection to change unit configuration settings. Interface software shall display and report current loop inductance measurements, current or last (historical) fault information, and information specific to the last vehicle detected and vehicle counts. Vehicle information shall include vehicle change of inductance, speed, length and time over loop.

2. A WindowsÔ based interface and data acquisition software program shall be provided to perform these functions via a remote reporting device running under a WindowsÔ 95 or WindowsÔ NT 4.0 operating system.

3. The software shall establish and maintain the communication link to a remote reporting device via a field modem or by direct connection to one of the serial ports on the detector.

4. The software shall be organized by application to simplify setup and monitoring of channel activity measurements, traffic counting, long-loop count, logging of vehicle speed and vehicle length, loop to loop travel time, detect durations, binning of count and occupancy, and sensing of vehicle travel direction with directional detection and call duration. 16727-15 09/02/04 CITY OF HOUSTON STANDARD SPECIFICATION TRAFFIC SIGNAL LOOP DETECTOR

5. The software shall allow selection of PC’s communication port and baud rate, and allow selection of English or metric measurements.

Baud rate options shall be 1200, 2400, 4800, 9600, or 19200 BPS.

Direct communication shall be via PC’s serial port or with telephone modem communications using one of the PC’s COM ports.

6. The software shall include a phone book and dialing utility.

7. The interface and data acquisition software shall provide a Read from Device command on the File menu.

It shall also provide for a unit address to be selected and allow the selection of a “wildcard” address to establish remote communication.

8. The Initial screen shall open with a Settings icon, a Real-Time Vehicle Logging icon and a Traffic Data Binning icon. After communications have been established with a detector, the other icons shall appear. These shall include the Real-Time Activity Monitoring icon, Force ALL Outputs and LEDs icon, a Reset icon and the Scan-Time icon.

9. A Settings window shall be divided into nine tabs to organize the detector settings by functional application.

10. A General tab shall allow selection of the configuration source to be either from EEPROM or switches, the oscillator frequency for the unit, the vehicle count period and channel sensitivity and mode. When the interface software reads settings from a unit, whichever configuration source is currently active shall determine which settings are displayed in boldface type (EEPROM or switch settings).

11. A Communications tab shall provide for the setting of a field modem command string, transmit delay, selection of the communication baud rates on the front and rear ports, for setting a programmable address and to enable a backpanel address. There shall be provisions to establish, cancel and change a password.

If password protection is set up in a detector, the unit shall not respond to any requests to perform a reset or change settings until the correct password has been issued. After a verified password has been issued the detector shall respond to all requests for reset or settings changes for 60 minutes. After 60 minutes the unit shall revert back to password protected mode until the password has been issued.

12. Reset shall cause immediate reinstatement of password protection. Most setting changes initiate a reset.

13. A Timing tab shall provide for setting the Delay or Extend Time options and the timing increments for each channel. There shall be an option to select “Enable” Green gating to condition the timing functions to green inputs.

14. A Microloop tab shall provide for selecting microloop mode of operation and setting some of the parameters that are unique to the performance of microloop sensors in special applications.

15. A Long-loop tab shall provide for selecting the option to count vehicles over long loops set to operate in Presence mode. Setup options shall be included to allow for calibrating the algorithm to improve count accuracy on loops of from 20 feet long to 60 feet long. Vehicle counts shall be available over the serial communication ports.

16. A Directional tab shall provide the option of setting up travel direction sensing on channel pairs 1 & 2. With the paired channels connected to 6-foot by 6-foot loops that are overlapped by three feet, vehicles shall be counted in both directions. The directional detection call output shall be assigned to the last loop a vehicle crosses when traveling in the direction that is to be detected. Call Duration shall be selectable for the directional output on the trailing channel of the paired sets.

17. An Output tab shall provide for the option to enable the Status Output for NEMA TS2 Type controllers. Software provision shall also exist to disable the "fail-safe" Call Output for unique system sampling applications.

18. A Noise Immunity tab shall provide for selecting several noise options including a power line filter which can be enabled.

19. An Adapt tab shall provide for selecting the adaptation parameters for the detector unit, to modify default operation.

20. A Real-Time Vehicle Logging icon shall provide for setting up channels to perform vehicle speed and length measurements.

Facilities shall be provided to insert a loop description (ID label), a loop type (configuration) and a calibration utility to select effective magnetic field loop sizes to improve measurement accuracy. The utility shall also provide for setting up loop assignments and leading edge distances from loop to loop to calculate vehicle speeds. This information shall be saved in the detector’s EEPROM.

Facilities shall be included to activate and view the log with channel IDs, the loop descriptions, dates, times, speeds, lengths, durations, loop to loop times displayed in real-time. Provisions shall be made to save the log to a file and print the log.

21. Traffic Data Binning icon shall open a window to setup and collect binned count and occupancy data from the detector.

A tab shall provide for setting up the channels to be binned, the start date and time, the end date and time, and the binning intervals.

The software shall inform the user when the detector will run out of memory based on the setup information provided. If continuous binning is selected the data shall “wrap-around” so that the oldest data will be overwritten with the latest entries.

22. A Real-Time Activity window shall be provided to display all current detection information pertaining to each channel, including current measurements, last fault (or historical fault) information, plus information specific to the last vehicle detected and traffic counts.

Measurements shall include: loop inductance, loop frequency, reference frequency, green input state and loop status.

Last Fault shall include fault type, time and date.

Last Vehicle data shall include Delta L in nanohenries, detect duration, detect time, and detect date.

Count shall display total count or directional count and the count period remaining.

23. The Activity window shall include a freeze capability to capture the current activity information and hold it for analysis while the software continues to display the most recent changes.

24. A utility window shall be included to verify the operation of a detector’s outputs and LEDs and confirm the wiring of a control cabinet to issue the call output to a device or controller. This utility shall allow selection of specific Detect LEDs, Call Outputs, Fault LEDs, and channel Status Outputs to be “forced” ON or OFF for testing the system.

25. A utility window shall be included to remotely reset a detector. It shall be possible to select specific channels, all channels or the entire unit. 16727-18 09/02/04 CITY OF HOUSTON STANDARD SPECIFICATION TRAFFIC SIGNAL LOOP DETECTOR

26. A utility window shall be included to provide a real-time view of the detector’s self-measured scan-time. This interactive utility shall continuously read and display the detector’s scan-time and display the theoretical detection performance based on user-selectable parameters such as loop to loop spacing, effective field lengths, channel sensitivity settings, and the effects of any noise immunity options selected.

27. The software shall allow printing of settings, activity measurements, and binned and logged vehicle data.

28. A comprehensive ON-LINE Help utility shall be included with detailed descriptions of unit features and setup information. The Help text shall include hyperlinks to all subjects related to applications or setup sequences. Help screens shall include a print function to print the page.

PART 3 EXECUTION

3.01 LOOP DETECTOR INSTALLATION

A. Each loop and its lead-in wires shall be separate and independent from any others. A minimum of twelve (12) inches shall be maintained between adjacent, parallel sawcuts. The Contractor shall be responsible for a good mechanical and electrical installation of the loop itself and the two lead-wires to and through the curb to the adjacent pull box or hand-hole. This responsibility shall remain with the Contractor until such time as the City can hook up, tune and test the loop for satisfactory operation.

B. Saw Cut: The sawed slot shall be 3/8 inch in width and a minimum of 2 inches in depth for concrete and asphalt. Sawcut shall be deep enough to provide one full inch of sealant above the installed loop wire(s). A sawed slot(s) must be continued from the nearest side or corner of the loop to the conduit thru the curb for the twisted lead-in wires to the adjacent pull box or junction point. The slots shall be brushed and cleared of any debris. Dry moisture-free compressed air shall be used to clear away the remaining dirt, dust and moisture. A one inch hole shall be drilled at each corner to eliminate sharp bends and damage to wire. Contractor shall remove sharp corner as illustrated on detail 3900-08 . Sawcuts shall overlap a sufficient distance to provide continuous full depth of the sawcut. There shall be no angle cuts for corners.

It is the City’s desire that loops are not installed across pavement joints. If a proposed loop would cross an existing pavement joint, the Contractor shall request confirmation from the Engineer. With prior approval from the Engineer, City shall

pay for additional sawcut to divide the proposed detection area into separate loops which cover the same effective area without crossing pavement joints.

C. The number of turns of loop wire shall be as shown on the drawings, or as follows:

Loop Perimeter, feet Number of Turns < 20 feet 4 <= 30 feet 3 > 30 feet 2

D. Positioning Wire: One continuous, unbroken, and unspliced length of wire shall be used to form the loop and its lead-in wires. This wire shall be of sufficient length for the required number of turns plus the distance to the adjacent pull box. The lead-in portion (pair of wires forming ends of loop) shall be twisted a minimum of five (5) turns per linear foot before insertion into slot. The twisted turns shall continue through the conduit at the curb and on to the pull box. Use a blunt tool to push wires into slot. The wires shall be held in place with rubber wedges or sections of insulation.

The sawcut, and loop wire installation shall be inspected by the City’s Inspector prior to placement of sealant. Failure to obtain inspection prior to placement of sealant will be reason to require the Contractor to completely reinstall the loop.

E. Sealing: Before and after sealing wires in roadway, test the pair of wires at the pull box for continuity and resistance with an ohm meter. In addition, the integrity of the insulation shall be checked by applying a megger between each end of the loop lead-in and the nearest reliable electrical ground (e.g., street light, hydrant, etc.). In the event that no available ground exists, a suitable ground shall be established for the measurement (e.g., driven metal spike). A resistance of less than ten (10) megohms to ground indicates a faulty installation and must be corrected. Final readings on each detector shall be given to the Inspector or Engineer on the job.

F. Sealer: Use embedding sealer as per manufacturer's instruction or as directed by Engineer. Loop sealant shall be allowed to cure for a minimum of three (3) hours prior to opening the lane for traffic.

G. Conduit: Wires from curb to pull box must be enclosed in conduit as indicated on plan set (1 in. min.) and twisted a minimum of five (5) turns per foot. The conduit shall be rigid in place.

END OF SECTION

16727-20 09/02/04